1. Technical Field of the Invention
The present invention relates to an electrical capacitance sensor.
It is to be noted that, for certain designated countries which permit the incorporation by reference, the contents described and/or illustrated in the documents relevant to Japanese Patent Application No. 2008-309408 filed on Dec. 4, 2008 and International Patent Application PCT/JP2009/070297 filed on Dec. 3, 2009 will be incorporated herein by reference, as a part of the description and/or drawings of the present application.
2. Background Art
For an electrical capacitance sensor having a film-based electrode section obtained by forming an antenna electrode and a ground electrode on the front surface of a film, known in the art is a technique of forming an additional ground electrode also on the rear surface of the film in order to prevent an erroneous detection (Patent Document 1). In such an electrical capacitance sensor, the antenna electrode and the ground electrodes are connected to a sensor circuit provided on another independent board via a connector, and the sensor circuit controls applying a certain voltage to the ground electrodes and detecting the value of a capacitance induced between the antenna electrode and an object.    [Patent Document 1] Japanese Patent Application Publication No. 2007-139555